The present invention relates to semiconductor device fabrication and integrated circuits and, more specifically, to structures for a laterally-diffused metal-oxide-semiconductor device and methods of forming a laterally-diffused metal-oxide-semiconductor device.
Device structures for a field-effect transistor generally include a source, a drain, and a gate electrode configured to switch carrier flow in a channel region arranged between the source and drain. When a control voltage exceeding a designated threshold voltage is applied to the gate electrode, carrier flow occurs in the channel region to produce a device output current. A fin-type field-effect transistor provides a device structure that that exhibits better electrostatic control of the channel region for improved Ion/Ioff compared to planar field-effect transistors.
High-voltage integrated circuits used, for example, in microwave/RF power amplifiers typically require specialized circuit technology capable of withstanding higher voltages. Laterally-diffused metal-oxide-semiconductor (LDMOS) devices are designed to handle higher voltages than logic field-effect transistors and may include additional features, such as an extended drain, that promote the higher voltage handling capability. Laterally-diffused metal-oxide-semiconductor devices may have a narrow safe operating area (SOA), which is defined as the voltage and current conditions over which the device structure can be expected to operate without experiencing self-damage, because of restrictions on breakdown voltage. For example, handling voltages exceeding nine volts may significantly increase the risk of breakdown and limit the safe operating area.
Improved structures for a laterally-diffused metal-oxide-semiconductor device and methods of forming a laterally-diffused metal-oxide-semiconductor device are needed.